All my thoughts about digital technology, robotics and innovation.

vha

Varnish Software just released a new version of Varnish High Avalability (VHA) 1.2 that boosts the following features plus some bug fixes in order to bring cache setups to be more efficiente and resilient:

ESI support: if you use dynamic content with Varnish, you are probably familiar with ESI. It allows you to include various objects inside a page on the server-side, letting Varnish build content using cached objects. VHA is now able to replicate this content, including all the multiple sub-requests caused by it, giving you replication without losing granularity in your content.

Better job scheduling: With v1.1 we gained support for multiple neighbors, but it was still a bit wild west-y, and in some circumstances, a slow neighbor could slow the replication for the other, well-behaved servers. This limitation has been fixed, letting the fast guys be fast no matter what.

Better autoscaling integration: VHA used to be very picky about its configuration file. Now it’s smarter and allows you to run/reload without neighbors for example. This permits an easier management of elastic clusters, a very popular setup. While not exactly part of VHA, I’d like to point out that we now have a ready-made solution to reconfigure automatically your VHA setup in a elastic cluster context. So if a neighbor is taken down or pops up, we’ll now and act on it.

Strict mode: Tight discipline also has its merits, and in a fixed setup, you may want to keep the old, picky behaviour as an effective error detection mechanism. Well, you can! You only need to activate an option, and you’re set.

Optional node name: VHA is able to use the hostname of the machine as it node name, making the ‘-m’ switch optional, and above all, adding genericity to the configuration.